Photographic shutter mechanism



Sept. 2, 1958 E. BURGER 2,849,937

PHOTOGRAPHIC sauma MECHANISM Filed May 14, 1953 INVENTOR ERICH BURGER ByS M HIS ATTORNEYS United States Patent 2,849,937 PHOTOGRAPHIC SHUTTERMECHANISM Erich Burger, Munich, Germany Application May 14, 1953, SerialNo. 354,971 Claims priority, application Germany May 21, 1952 8 Claims.(Cl. 95-63) This invention relates to a photographic shutter mechanismof the multiple sector type, and more particularly, to a linkage systemfor actuating said shutter in such manner as to eliminate inefficaciesdue to the inertia of the moving parts. Specifically, the presentinvention relates to an improved sector shutter operating linkage systemin a plurality of elastic members which are so arranged as to actuatethe shutter mechanism at high speeds without vibration or fluttering.

The present invention comprises an improvement over the shutteroperating mechanism disclosed in my prior U. S. application, Serial No.236,484, filed July 13, 1951, in which the actuating linkage was soarranged that the shutter was operated to less than full opening underthe power stroke of the linkage mechanism, reliance being placed uponthe power linkage and a resilient stop member to provide full shutteropening by overtravel of the driven mechanism under the effect ofinertia. In the instant invention the shutter opening linkage mechanismis provided with more than one resilient or elastic member in suchmanner that the stresses and strain on the mechanical parts isconsiderably reduced whereby the life of the device is greatlyincreased. It has been found that this form of operating linkage furtherreduces vibration of the shutter sector whereby foggy and distortedimages are substantially completely eliminated while retaining theexceptionally short exposure times, up to of a second, obtained by theconstruction in said prior application.

According to the instant invention the shutter sector actuating means isboth driven and stopped by means of adjustable elastic projections, thedriving projection being formed as a push link mounted upon aconventional shutter actuating lever, and the stopping projection beingformed as an integral part of the conventional base plate. In order toprovide a readily operable and stable adjustment system for changing theexposure period, the adjustable push link and stop projections are eachprovided with cam-like step formations for cooperation with a portion ofthe shutter operating ring.

A distinct feature of the present invention resides in the provision ofmeans on the main actuating lever for cooperating with the shutteroperating ring in such manner that the sector operating ring is reversedin direction of movement during a portion of the shutter opening stroke,whereby even shorter periods of exposure than heretofore have beenobtained are possible.

Accordingly, a prime object of the present invention is to provide animproved sector shutter operating linkage. Another object of theinvention is to provide a shutter operating linkage system for obtainingexposure periods of less than A of a second. Other distinct objects willbecome apparent from the description and claims that follow.

Having broadly disclosed the invention reference will now be made to thedrawings in describing a specific example of the same, and in which:

Fig. 1 diagrammatically illustrates a portion of a sector ice 2 shutterlinkage system in its tension condition, and when adjusted for mediumexposure times,

Fig. 2 illustrates the shutter linkage system in tension condition, andwhen adjusted for relatively long exposure times, and

Fig. 3 illustrates the shutter linkage system at the time when areversing in the direction of movement of the sector ring occurs.

In the embodiment of the invention illustrated in Figs. 1 through 3inclusive, the sector shutter operating ring 1 is mounted for rotationin the usual manner and is normally biased in the direction of shutterclosing (or return movement) by means of a weak spring 2. As shown inFig. 1, ring 1 is in its shutter closed position, and has a stop nose 1aprojecting laterally therefrom and riding against the extended end of aresilient stop projection 3. In order to actuate the shutter ring, amain actuating lever having a cam shaped disc-like portion 4 and atensioning lever arm 5 is pivoted externally to ring 1 and adapted torotate about its pivot for cooperation with the sector operating ring ina manner subsequently to be described by means of a tension spring 14.Normally the actuating member 4, 5 is held in its tensioned position bymeans of a latch or release lever 6 having a latching nose for engagingand abutting a recessed cam portion on disc portion 4, as shown in Fig.1.

The actuating lever 4, 5 is connected with a push link 7 by means of abearing pivot 8 carried by the disc portion 4. Push ring 7 includes anintegral step-like nose portion 7a which serves as the driver mechanismfor actuating the sector operating ring 1 in its sector openingdirection, and a reduced, spring-like, curved portion adjacent to thepivot 8 for providing an inherent elasticity or resiliency in the link.Actuating link 7 is normally urged to rotate about its pivot 8 in acounterclockwise manner by means of a spring 13 connected between link 7and lever portion 4, but is held against full counterclockwise movementby virtue of contact with an abutment pin 9a carried by an extension ofa resilient reversing lever mechanism 9. The abutment pin 9a bearsagainst .the curved underside of link 7 in the manner illustrated, andprovides a guiding surface for controlling the direction of movement oflink 7 towards an actuator projection 1b, carried on shutter operatingring 1.

The reversing lever mechanism 9 includes a step-like, or cam-like,stopping portion 90, and which is normally positioned in the path ofmovement of the operating projection 1b on sector ring 1. Lever 9 alsoincludes a spring-like resilient portion 9d which is positioned betweenthe pivot 11 of the lever and the extended end carrying abutment pin 9aand cam stop portion 9c. This arrangement provides the abutment pin andcam stop portion with an inherent elasticity or resiliency for a purposehereinafter apparent.

The stepped cam-like portion is adapted to be moved with respect to theprojection nose 1b of sector ring 1 by pivoting lever 9 about its pivotpin 11, the lever 9 being provided for this purpose with an actuatingarm 9b having contact with an eccentric cam member 10 by means of abiasing spring 12. The arrangement is such that spring 12 normally tendsto rotate lever 9 in a counterclockwise direction about pivot 11, thelimit position of the lever being controlled, however, by rotation ofeccentric 10, whereby the stepped reversing cam portion 9c may beadjusted in a pre-set manner for cooperation with nose lb of sector 1.

Actuating lever 4, 5 also carries a sector ring reversing projection 4aon the disc portion 4, which projection is adapted to contact the stopnose projection 1a on sector ring 1 (as shown in Fig. 3) upon movementof the actuating lever 4, 5 through approximately the mid-point of itsshutter opening stroke.

Having described the structure of the operating linkage, reference willnow be made to the same in cooperative relationship, in describing theoperation of the mechanism. As shown in Fig. 1,,the linkage mechanism isset in its tensioned condition with the shutter ring in its shutterclosed position. By pivoting latch lever 6 in a clockwise direction,lever 4, is released under the action of main spring 14 and proceeds torotate in a counterclockwise direction (as shown in Fig. 2) to bring thestep-like portion 7a of link 7 into contact with the actuating noseportion 1b to drive sector ring 1 in a counterclockwise directionagainst the tension of spring 2, the ring 7 being guided in its forwardstroke by contact with the abutment pin 9a.

However, due to the factthat link 7 is providedwith the stepped camcontour 7a, the link will always be initially positioned with. a slightclearance between it and ring nose projection 1b so that the link may begreatly accelerated before striking the ring nose projection. Thisarrangement substantially shortens the actual shutter opening operationand is a main factor in eliminating vibration, the elastic, bow-likeportion of link 7 providing a cushioning action without substantiallydetracting from the rapid acceleration provided. It will be apparentthat this constructionalso serves to permit the obtaining of shorterexposure periods.

Continued rotation of the main actuating lever will cause actuating link7 to rotate about pivot 8 and against the tension of spring 13 in themanner illustrated in Fig. 3 to move the nose portion 7a out of the pathof the ring nose portion 112. Simultaneously nose portion 1b contacts onthe surface of reversing cam portions 9c of lever 9 to substantiallystop shutter ring 1 in its shutter opening movement. However, due to theinherent resiliency of lever 9, through the intermediate of the bow-likestructure 9d, reversing projections 9c do not constitute a full andpositive stop to the continued forward movement of ring 1. The ring thuscontinues to or in (depending on the setting of lever 9) its fullshutter opening movement under the influence of its own inertia.

Subsequently, the ring inertia is overcome and the energy stored in theflexed bow-like portion 9d of lever 9 causes a reversing in thedirection of movement of the shutter ring to return it in a shutterclosing direction. At approximately this instant, the reversingprojection in on main actuating lever 4, 5 comes into contact withprojection la on sector ring (as illustrated in Fig. 3) and positivelydrives the sector operating ring in a shutter close direction, i. e., ina clockwise direction, the weak return spring 2 assisting projection 4aand the stored energy in resilient reverse lever 9 in this action. Itwill be realized, of course, that the above description of the operationof the linkage with reference to Figs. 1, 2 and 3 is merely exemplarysince the illustrations of Figs. 1, 2 and 3 depict the linkage structurewhen adjusted for different exposure times.

Adjustment of the exposure period is readily provided by rotating thecam 10 to cause lever 9 to rotate in a clockwise direction about pivot11 and bring the step-like projection 90 into a different alignment withthe operating nose portion 1b of ring 1. Simultaneously with adjustmentof lever 9, the abutment pin 9a will be adjusted with respect toactuating link 7, and by virtue of the curved edge contacting surfacelink 7, will cause such link to rotate either clockwise orcounterclockwise about pivot 8 under the influence of pin 13 to alterthe position of actuating nose 7a with respect to the sector ringoperating nose portion 1b in like manner to the movement of reversingcam projections 90. It will thus be apparent that various exposureperiods may be provided for by a suitable choice of step-likeprojections 7a and 9c on the respective members.

' It will also be obvious that further adjustments may be provided bymounting the anchor pin for the main tensioning spring 14 of theactuating lever 4, 5 on a suitable adjustable base, as for example, on alever actuated by means of a cam-bearing timing ring as set forth insaid prior application. For this purpose the latch lever 6 may beprovided with a plurality of step-like latch projections for cooperatingwith the notch on disc portion 4 in any one of the pre-set positions oflever 4, 5 and spring 14. With such constructions it will be apparentthat not only will the step-like projections and 7a be adjusted withrespect to the ring projection 1b through the rotaion of eccentric 10,but that the step-like cam nose 7a of link 7 may be further manipulatedto provide an additional change in the exposure time. Such anarrangement makes it possible to use the control of step-like camportions 90 and 7a by lever 9 as a rough setting, while adjustment oflever 4, 5 and spring 14 may serve as a fine setting.

As many apparently widely different embodiments of this invention may bemade without departing from the spirit and scope hereof, it is to beunderstood that the invention is not limited, except as defined in theappended claims.

What is claimed is:

l. A photographic lens shutter mechanism comprising a shutter operatingring, projecting means mounted upon said ring, actuating means fordriving said ring in a direction to open said shutter, movable meansmounting said actuating means to move into contact with said projectingmeans for driving said ring in a shutter-opening movement, reversingmeans disposed in the path of movement of said projecting means fordriving said ring in a shutterclosing movement, elastic meansincorporated in said reversing means to permit said ring to continue inits shutter-opening movement after contacting said reversing meansbefore said reversing means initiates said shutterclosing movement, andcontrol means operatively engaged with said actuating means and withsaid reversing means for varying the force imparted to said projectingmeans by said actuating means and the amount of travel of saidprojecting means before it contacts said reversing means, said controlmeans increasing said force to pro vide higher shutter speeds withconcomitant earlier contact with said reversing means to maintain saidaperture opening substantially constant over the entire range of shutterspeeds.

2. A photographic lens shutter mechanism as set forth in claim 1 whereinsaid actuating means is comprised of an arm pivotally mounted upon arotatable member, spring means is attached to said rotatable member toresiliently urge it in a direction to cause said arm to contact saidprojecting means, and latch means is operatively associated with saidrotatable member to hold it against the force of said spring in a cockedposition.

3. A photographic lens shutter mechanism as set forth in claim 2 whereinsaid arm includes a resilient portion for minimizing the shock impartedto said shutter.

4. A photographic lens shutter mechanism as set forth in claim 2 whereinsaid reversing means includes a reversing lever, said arm and said leverincluding reversely stepped contacting surfaces for engaging saidprojecting means, said control means 'being operatively associated withsaid reversing lever for aligning a predetermined step with saidprojecting means, and said reversing lever being operatively engagedwith said arm to align reversely corresponding steps of said reversinglever and said arm with said projecting means to cause said reversinglever to contact said projecting means earlier as said projecting meansis driven with greater force by more highly accelerated steps positionedmore remotely from said projecting means to maintain said apertureopening constant over said entire range of shutter speeds.

5. A photographic lens shutter mechanism as set forth in claim 2 whereinsaid reversing means includes an extension disposed upon said rotatablemember and a corresponding extension upon said sector operating ringwhich contact each other to react upon said spring means to aid inresiliently causing a shutter-closing movement of said ring.

6. A photographic lens shutter mechanism as set forth in claim 4 whereinsaid arm slides against a pin mounted upon said reversing lever toproperly align said steps.

7. A photographic lens shutter mechanism as set forth in claim 1 whereina weak return spring is operatively coupled to said ring.

8. A photographic lens shutter mechanism as set forth in claim 4 whereinan eccentric is operatively engaged with said lever to vary saidalignment of said lever and said arm.

References Cited in the file of this patent UNITED STATES PATENTS

